Electrical gun sight control



Dec'. 14, 1948. P. R. WHEELER ELECTRICAL GUN SIGHT CONTROL 2 Sheets-Sheet 1 Filed Nov. 8, 1945 INVENTOR PHILLIP R WHEELER ATTORNEY Dec. 14, 1948. P. R. WHEELER ELECTRICAL GUN SIGHT CONTROL 2 Sheets-Sheet 2 Filed Nov. 8, 1945 ml w vm m. t D. t 1 :1 E Q q 2 Q Ii... aw 7 R R k .G MK Q .0 MR 2 & mu .8 R

PMLL/PRMfEZE/i Patented' Dec. 14, me

UNITED STATES PATENT OFFICE 2,455,963 ELECTRICAL GUN SIGHT CONTROL Phillip Rood Wheeler, Alexandria, Va. Application November 8, 1945, Serial No. 627,515 1 Claim. (Cl. 177-451) (Granted under the act of March 3, 1883. amended April 30, 1928: 370 0. G. 757) The present invention relates to potentiometeis. While it has a wide range of prospective application, it is of particular utility in an indicating system of the type including means for providing areference mark, means for deflecting the reference mark in one coordinate direction by an amount functionally related to a first electrical signal, and means for deflecting the reference mark in a second coordinate direction by an amount fimctionaliy related to a second electrical signal, whereby the reference mark is positioned in a frame of Cartesian coordinates to provide an indication. In accordance with the invention there is provided a novel control arrangement for controlling both of those deflecting means. It comprises a control member, the ultimate function of which is to order the position of the reference mark, means responsive to displacement of the control member in one coordinate for ying the first electrical signal, and means responsive to displacement of the control member in another coordinate direction for varying the second electrical signal, whereby displacement of the control member in its frame causes a corresponding displacement of the reference mark in its frame.

The present application is a continuation-inpart of my co-pending patent application Serial No. 510,403, now abandoned, filed in the United States Patent Omce on November 15, 1943, and entitled Cathode-ray gun sight.

It is an object of my invention to provide a relatively simple and inexpensive potentiometer having such structure and operation that it is adjustable in two coordinates to produce deflection of a reference mark in corresponding coordinates.

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following specification, to the claim appended thereto and to the accompanying drawings in which:

Fig. 1 is a perspective view of a novel potenti-= ometer in accordance with my invention;

Fig. 2 is a cross-sectional view of the potentiometer illustrated in Fig. 1;

Fig. 3 is an exploded view of the moving parts of the potentiometer shown in Fig. 1;

Fig. 4 illustrates the application of my improved potentiometer control arrangement to a gun sight; and

Fig. 5 illustrates the application of my improved potentiometer to a cathode-ray tube beam-positioning system.

In Fig. 1 there is disclosed a control arrangement comprising a support, a first variable voltage divider secured to said support in one coordinate, a second variable voltage divider secured to said support in another coordinate, a control member movable inboth of said coordinates, means actuated said means being independently displaceable.

position of contact I! on adjusts the voltage-dividing ratio of potentiom- The arrangement comprises a housing l2 functioning as a supporting member and having a suitable electrical plug it extending from one wall thereof. Mounted within the housing are two variable voltage dividers or potentiometers It and I5. Potentiometer I4 is secured to the front of the housing and is adjustable in the left-right coordinate direction. Potentiometer I5 is secured to the right side of the housing and is adjustable in the "fore-aft coordinate direction. Each of the potentiometers includes its individual one of'sliding contacts I i, ll. Each of the sliding contacts is mounted on its indi-- vidual one of movable bars I 8, I9. Each of the bars is formed with a longitudinally disposed central slot 20, 2|. The ends of the bar is are doubled back and secured to a cable 22. The ends of bar I! are similarly secured to a cable 28.

The embodiment of my invention illustrated in Figs. 1-3 also includes a control member or knob 24. This control member is movable in two directions in its frame of Cartesian coordinates. When it' is moved to the left or right it adjusts the setting of contact arm I'S on potentiometer l4 and therefore adjusts the voltage-dividing ratio of the. potentiometer. Similarly, movement of knob 24 in the fore or aft direction varies the potentiometer l5 and eter l5. The control knob is secured to a vertically extending shaft 25, which passes through the slots-20 and 2| in bars I! and I9. Suitable stops 2!; and 21 at the upper and lower ends, respectively, of shaft 25 prevent longitudinal movement of the shaft but permit movement thereof in any lateral direction.

When knob 24 is displaced in a direction parallel to arm l9, shaft 25 merely slidably moves within slot 2| and contact arm I! does not move; under this assumed condition shaft 25 displaces arm l8. Additionally, movement of knob 24 in a direction parallel to bar It does not cause move. ment of contact arm is but does displace contact arm l1. Thus the two means for varying the settings of the potentiometers are independently movable while both are actuated by the control member 24. Suitable graduated scales are provided on the upper surface of an index member 28 secured to housing i2. Secured to control knob 24 are index pointers 29 and 30. Scale 34 is calibrated in terms of the final result of motion 3 oi. contact armi"l, whether; that. result involves the. positionof. a cathode. ray'tube. spot in one coordinate, thev setting of: the: sight? angle of a gun sight. and therefore, thefiringxange. or elevation of a gun, or; any similar phenomenon, depending upon. the application in which the. po-

tentiometer is employed. Similarly, scale 35 ,is' calibrated in terms of the result produced by adjustment of: contact. arm I. on: potentiometer 1 Referring now specifically to Fig. 4 of the drawing there is illustrated in schematic form a gunsighting system in which my improved potentlometer is included for spotting purposes. This arrangement includes -a lead-computing gun sight 4| of the general class shown in United States Patent No. 1,724,093, issued to Robert Kauch and Charles L. Paulus on August 13, 1929. This gun sight includes a reference mark provided by the intersection of a vertical cross-hair 42 and a horizontal cross-hair 43. The general operation of such lead-computing sights is such that when the gun sight operator superimposes the reference mark on the target the sight angle (or'angle between the line of sight and the line of fire in the vertical plane) and the sight deflection angle (or deflection of the line of sight from the line of fire in the slant plane) are of the computed values appropriate to so position the line of fire that a hit should be obtained on the target. Cross-hairs 42 and 42 are individually secured to levers 44 and 45 and these levers individually constitute the pointers of galvanometers 46 and 41. The construction and operation of elements 42 to 41, inclusive, are the same as the structure and operation of the corresponding elements shown in Figs. 4 and of said United States Patent No, 1,724,093, and are well known to those skilled in the art,so that further description thereof is deemed unnecessary. The

galvanometers constitute the means for deflecting the reference mark provided by the cross-hairs.

Let it be assumed that gun fire is being directed to a stationary target and that the reference mark provided by the intersection of crosshairs 42, 43 so disturbs a line of sight with reference to a line of fire that the line of fire represents the theoretically correct solution of the fire control problem posed by data available. Let

it be further assumed that in spite of this apparently correct solution a series of misses is scored, as indicated by tracer fire. By watching the paths of tracers 'from the gun a spotter is able to ascertain in which directions the gun fire is missing the target.' My improved control arrangement provides a device by which a spotter located at the gun or at some observation point remotely removed therefrom may introduce spotting corrections which disturb the line of sight with reference to the gun by a corrective amount, prompting the gunner to keep the gun bore properly directed with reference to the target and facilitate the scoring of hits.

The terminals of potentiometer N are couple put portion of potentiometer ll.

4; to a voltage source II, a center tap on the potentiometerbeing connected to a. center tap on the source, Potentiometer II is similarly coupled to-a; voltage source Ii. The potentials applied to; galvanometer 48 comprise the drop in resistor 44' and; the drop in that portion of potentiometer 14 between the contact I and the center tap. Similarly, galvanometer 41 is actuated by the potentials in resistor II and the out- Neglecting for the moment the operation of potentiometers i3 and 54 it will be seen that the setting of contact arm is on potentiometer I4 is at least in part determinative of the deflection of galvanometer 48 and the position of cross-hair 42. Likewise, the setting of contactarm H on potentiometer I! is determinative at least in part of the deflec- 1 tion of galvanometer 41 and the resultant position of cross-hair 43. ,By moving control knob 24 to the left or right the operator causes crosshair 42 to be moved to the left or right, as appropriate. Likewise, by moving control knob 24 fore or aft the spotter causes cross-hair 42 to be elevated or depressed, as appropriate. Scales 24 and may therefore be calibrated in terms.

of the yards of range or mils of deflection, respectively, introduced by the spotting correction.

My improved control arrangement is of equal utility for introducing spotting corrections during fire on a/moving target. In accordance wtih the teachings of United States Patent 1,724,093, here inabove referred to, and of United States Patent No. 1,322,153; issued November 18, 1919, to J. S. Wilson and W. E. Dalby, there are included in gun sight 4| a generator 85 for generating an electrical signal proportional to the train component of the rate at which the sight tracks a target. Similarly, there is provided an elevation generator 54 for generating a voltage proportional to the elevational component of the rate at which the sight tracks the moving target. The

lead angle by which the line of flre should lead the line of sight in order to produce hits on a moving target is functionally related to the product of the-tracking rate and the time of flight. In practice the tracking rate is automatically estabiished by keeping the line of sight on the target and the time of flight factor, considered to be directly proportional to range for a given anti-aircraft gun, .is' introduced by a range setting. F'or this purpose, the output circuits of generators 55 and 56 are coupled to the input circuits of potentiometers 53, 54, respectively. As a range setting expedient, the sliding contacts in the output circuits of potentiometers II and 54 are gauged by any appropriate means indicated by the dashed line 51. The voltage outputs of potentiom'eters 53 and 54 for any given tracking rate are controlled in accordance with range by varying the setting of potentiometers 53 and i4. Potentiometer 52 applies to galvanometer .45 "a signal proportional to the train component of the desired lead angle and potentiometer 54 applies to galvanometer 41 an electrical signal having a magnitude proportional to the elevational component of the desired lead angle. The polarities of the signal outputs of generators i5 and 59 are such that the directions of the resultant deflections of cross-hairs 42 and 42 are related to the directions of motion of the target in the train and elevational coordinates, respectively. As explained in the above-mentioned copending patent application and in the issued patents hereinabove referred to, elements 53, 54, 55, it and 51, in co peration with elements 42 to 41 inclucenter of resistor l6.

sive, so deflect the reference mark provided by the intersection of cross-hairs 42, 43 and cause the line of sight to be so disturbed with respect to the bore axis of the gun that the line of fire is caused to lead the line of sight by the proper computed amount (due to the action of the gunner in so moving the gun and sight as to keep the line of sight on the target) Assuming the proper computation of the lead angle from available data, and assuming further that the spotter observes that misses are being scored, the spotter moves control knob '24 and deflects the reference mark in order to cure these errors. This is done as effectively in antiaircraft flre as in fire on a stationary target.-

In Fig. there is disclosed an indicating system of the cathode-ray tube type and including my improved voltage control arrangement for horizontal and vertical spot positioning. The circuit there illustrated was substantially copied from Fig, 1825, page 397, the Radio Amateurs Handbook, twentieth edition, 1943, published by the American Radio Relay League, Incorporated, West Hartford, Connecticut, so that a full description thereof is not necessary. Briefly however, there is shown a bleeder resistor comprising resistors 60 (30,000 ohms), 6| (30,000 ohms), 62 (75,000 ohms), 63 (50,000 ohms, variable), and 64 (25,000 ohms, variable). Resistors 60 to 64 are connected as a series combination and are adapted to be coupled to a 400-600 volt direct current source. The junction of resistors 80 and 6| is grounded. In shunt across this combination is a condenser 65 (8 microfarads). This bleeder resistor supplies suitable potentials to a cathode ray tube 66. The cathode of this tube is connected to the junction of resistors 63 and 64 and is therefore negatively biased with respect to ground. Since the second anode 61 of tube 66 is grounded, it is positive with respect to cathode 68. The control electrode 69 is negatively biased with-respect to the cathode by connection to a sliding tap on resistor 64, through resistor 10 (300,000 ohms). The first anode H is positively biased with respect to the cathode by connection to a sliding tap on resistor 63. Vertical beam-deflecting plate 13 and horizontal beam-deflecting plate 14 are grounded. Tube 66 includes a fluorescent screen. The beam from the electron gun structure 68, 69, II and 61 causes a spot to appear on this,screen. For the purpose of positioning this spot there are provided positioning controls l4, it in the particular form shown in Figs. 1 to 3, inclusive. The resistor portions of potentiometers l4 and I 5 are connected in parallel with the series combinations of resistors 60 and 6|. Suitable values for resistors I4 and I6 are one (1) megohm each.

Horizontal deflecting plate 16 is connected to contact arm "5 through a resistor 11 (5 megohms) and vertical deflecting plate 16 is connected to contact arm I! through a resistor 18 (5 meg-. ohms). Since the junction of resistor 60 and 6| is grounded deflecting plate 16 is at the same potential as deflecting plate II when contact arm .I6 is on the central electrical point of resistor ll. Similarly, deflecting plates 13 and 16 are at the same potential when contact arm I! is at the when contact arm I6 is moved to the left plate 16 becomes more positive than plate It and the electron beam, being negatively charged. is deflected to the left. Likewise, movement of contact arm II in the aft direction makes plate 16 more negative than plate f .13 and causes the spot to be elevated. Conversely the spot is deflected to the right when arm I! copending patent application hereinabove referred to. Signals representative of desired train vand elevational lead components may be applied to plates 13, I6 and plates M, 15 by input circuit conductors 8| and 82, respectively, connected to the Junction of resistor 18 and deflecting plate 16 and the junction of resistor 11 and deflection plate 15, respectively.

While there has been shown and described what is at present considered to be a' preferred embodiment of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the true scope of the in. vention, and it is, accordingly, intended in the appended claim to cover all such changes and modifications as fall within the true scope of the invention and without the proper scope of the prior art. For example, my invention comprises rheostat structures as well as potentiometer structures.

The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

In a gun mounted for training and elevation movement and having a gun sight provided with a reference mark and means for deflecting the reference mark in one coordinate direction by an amount functionally related to a first electrical signal and means for deflecting the reference mark in a second coordinate direction by an amount functionally related to a second electrical signal, whereby said reference mark is positioned in a frame of Cartesian coordinates to provide an indication the combination of, a control arrangement for adjusting both of said deflecting means comprising a manually displaceable control member, means responsive to displacement of said control member in one coordinate direction for varying said first signal and means responsive to the displacement of said control member in another coordinate direction for varying said second signal, whereby displacement of said control member in its frame causes displacement of said reference mark in its frame.

PHILLIP ROOD WHEELER.

REFERENCES crrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Italy Dec. 12. 1938 

